1. Field of the Invention
This invention relates generally to a mechanically actuated plug and, more particularly, to a mechanically actuated plug for use with a recirculation suction line in a Boiling Water Reactor plant.
2. Description of Prior Art
In a Boiling Water Reactor ("BWR") plant, it is often necessary, for example during maintenance work, to block a recirculation suction line so that the appropriate reactor water level may be maintained during a refueling operation. Typically, a pneumatically controlled plug is used to block the recirculation suction line.
The pneumatically controlled plug is suspended from an electric hoist through stainless steel cables. Once the plug is moved into position over a core shroud, or a reactor annulus, the plug is lowered using the electric hoist. A pneumatically controlled insertion device is then used for inserting the bottom end of the plug into a nozzle of the recirculation suction line.
The pneumatically controlled plug, however, suffers from a disadvantage that several pneumatic lines travel from the plug to a control panel, which is located on the refueling floor level at a location remote from the plug. These pneumatic lines complicate the procedure for installing the plug into position at the recirculation suction line. The pneumatic lines also make the refueling operation difficult since the procedure must be performed while maneuvering around the pneumatic lines.
Furthermore, the hoist lines for manuvering the plug must be "fished" around obstacles in the reactor.
Thus, the plugging of the recirculation suction line is a complicated operation involving the use of pneumatic lines, hoses, connectors, and the control panel. A significant amount of time is consumed in its operation.